Tire cord fabric (normally consisting of a layer of like cords of filamentary material) is usually made by the manufacturer thereof from cords purchased from a cord producer. Each tire cord fabric manufacturer will, of course, have several sources of supply of cords. It may sometimes become essential to be able to identify the source of a given batch of tire cords once the same has been used to form a given fabric lot, for example if the ultimate tire manufacture finds that lot of tire cord fabric to be defective in one property or another of the cords, or perhaps to have led to the manufacture of defective tires.